It was usually the custom for the deceased royal person to have a Chief Mourner in place of the monarch. For example, when Queen Jane Seymour died, the chief mourner was her step-daughter Mary Tudor. When Catherine Parr died, the chief mourner was Lady Jane Grey. In this case, the chief mourner for Queen Mary was her cousin, Margaret Douglas, Countess of Lennox.

Yes, nowadays the new monarch does attend the late monarch's funeral. As Roland says, the princes of the immediate family keep vigil over the coffin in Westminster Hall at the lying-in-state and walk behind the cortege. The nearest we have seen to such a funeral in the last 50 years was that of the Queen Mother, when Prince Charles and his brothers kept vigil for a few hours.

There is a video on You Tube of the coffin of George V leaving Westminster Abbey on the gun carriage; the new king and his brothers walk behind and we see Queen Mary getting into a coach for the journey to the royal vault at Windsor. (No doubt the funeral of George VI will be on there as well.)

The remarkable photograph Lara mentions of the three queens at the funeral of George VI was taken by Ronald Case who was working for a newspaper and did not make a penny from it; he died last September aged 82. 'Three Queens in Mourning' is regarded as one of the 100 greatest photographs of the twentieth century.

HiIt was customary for tudor monarchs (royal family) not being allowed to see death..perhaps a belief that seeing death would cause it upon themselves? For example, when Prince Arthur died in 1502 - neither his wife- Catherine of Aragon or his parents - Elizabeth of York and Henry V11 were allowed at the ceremony . Hope this helps.

I have understood that in earlier times that the presence of the Monarch at a funeral might cause subjects to have thoughts of the mortality of the Sovereign. To think upon the death of the King or Queen would be tantamount to treason.